Support the Arctic Sea Ice Forum and Blog

Author Topic: 2018 sea ice area and extent data  (Read 98461 times)

gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #600 on: May 15, 2018, 12:05:34 PM »

One point about the CAB, in reality it is bunch of areas that have different ice melt characteristics. In general, it would be best if NSIDC decided to split the CAB into several sub-geographies, with reprocessing of past regional data, as rapid changes in a small sub-area are masked by bundling into the CAB super-area.

Too many graphs! But wouldn't it be nice if the image in your post, made very transparent, (plus some lines dividing up the Central Arctic Sea in line with your idea), was used as a watermark to put on some of the sea ice extent, area, concentration and thickness images. At least then remarks on where things were happening could easily be related to their physical location.

But well beyond my capability with graphics.
"Para a Causa do Povo a Luta Continua!"

gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #601 on: May 15, 2018, 02:26:32 PM »
NSIDC Total Area as at 14 May (5 day trailing average)

The first table attached shows how area loss has increased to 70k+ over the last 2 days. When Hudson Bay, the Okhotsk Sea and the St. Lawrence are excluded, it is 68k.

Pacific Side
The Okhotsk loss of area has slowed to 1k and will soon be more or less irrelevant.
The Bering Sea area is 7k, and is irrelevant.

However, in the last two days:-
Chukchi Sea has lost 29k km2 in area,
The Beaufort Sea has lost 26k km2 in area.
The melting season has arrived in the Pacific side of the Arctic Basin?

Atlantic Side

- Warmth moving up Baffin Bay has caused an area loss of about 28k over the last 2 days.
- The Greenland area loss in the last two days was 13k.
- The Barents area loss has slowed a bit , but still a 30k loss in the last two days.
- The Laptev Sea and  Kara Sea are stable,
- Other Central Seas area loss is minimal.


The great warming event has stopped for the moment. GFS say it will get going again after next week, but they always do, and just sometimes it arrives.
[/quote]
[/quote]
"Para a Causa do Povo a Luta Continua!"

oren

  • ASIF Upper Class
  • Posts: 2044
    • View Profile
  • Liked: 39
  • Likes Given: 79
Re: 2018 sea ice area and extent data
« Reply #602 on: May 15, 2018, 05:28:04 PM »
Just to complete the discussion, this is the map used by Wipneus for the AMSR2 regional graphs, based on the Cryosphere Today mask. In this map the CAB is larger than on the NSIDC map, with the Beaufort, Chukchi, ESS and Laptev all smaller, and also a slightly different cutoff at the Fram.

Shared Humanity

  • ASIF Governor
  • Posts: 2701
    • View Profile
  • Liked: 27
  • Likes Given: 2
Re: 2018 sea ice area and extent data
« Reply #603 on: May 15, 2018, 05:32:24 PM »
Just to complete the discussion, this is the map used by Wipneus for the AMSR2 regional graphs, based on the Cryosphere Today mask. In this map the CAB is larger than on the NSIDC map, with the Beaufort, Chukchi, ESS and Laptev all smaller, and also a slightly different cutoff at the Fram.

It would make sense to use the same map.

gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #604 on: May 15, 2018, 06:22:32 PM »
Just to complete the discussion, this is the map used by Wipneus for the AMSR2 regional graphs, based on the Cryosphere Today mask. In this map the CAB is larger than on the NSIDC map, with the Beaufort, Chukchi, ESS and Laptev all smaller, and also a slightly different cutoff at the Fram.
I am confused again - so please remind me which is the goddam NSIDC map.
Please please please.
"Para a Causa do Povo a Luta Continua!"

Neven

  • Administrator
  • ASIF Royalty
  • *****
  • Posts: 5084
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 58
  • Likes Given: 36
Re: 2018 sea ice area and extent data
« Reply #605 on: May 15, 2018, 09:15:40 PM »
Just to complete the discussion,

Hold on, I want to say one more thing.

It'd be interesting to divide the CAB up to 80N, or perhaps up to the pole hole, but only after July is over, because most regions have melted out by then, except for the ESS. Or let me put it this way, I wouldn't report on any of those inner CAB regions until then on the ASIB (unless there's something like a Laptev bite). It would otherwise be very confusing for newcomers.

"The ESS hasn't fully melted out yet, but already in the ESSiCAB region there is divergence, which means that..."  ;)
Il faut cultiver notre jardin

oren

  • ASIF Upper Class
  • Posts: 2044
    • View Profile
  • Liked: 39
  • Likes Given: 79
Re: 2018 sea ice area and extent data
« Reply #606 on: May 15, 2018, 10:11:37 PM »
Neven - you are right. indeed, the CAB used to be one geographical region - the place that never melted. But nowadays there's the CAB region that barely ever freezes (north of Svalbard), the areas that often melt in July and August, and the core that still remains unmelted, though barely. But most of the year everything lumped into the CAB will show very stable extent numbers.
Gerontocrat - the original image I posted was of NSIDC regions, while the second one was of CT regions, which Wipneus uses for his AMSR2 calculations as well. Why the two maps are different is beyond my pay grade, but I'm sure someone knows the history of that.

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #607 on: May 16, 2018, 05:53:49 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 15th, 2018: 11,671,777 km2, a small drop of -6,031 km2.
2018 is the second lowest on record.
2018 has 409,416 km2 more than 2016 and 195,504 km2 less than 2015.

Just by sight, I think that a freeze on Hudson Bay made a contribution to have the small drop.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #608 on: May 17, 2018, 06:33:56 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 16th, 2018: 11,630,844 km2, a drop of -40,933 km2.
2018 is the second lowest on record.
2018 has 432,935 km2 more than 2016 and 175,676 km2 less than 2015.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #609 on: May 17, 2018, 11:58:18 AM »
JAXA DATA 11,630,844 km2(May 16, 2018)

Just to add to Juan's post :
- Extent loss has been below average for the last 4 days, hence 2018 extent is now just 298k km2 less than 2017,
- 2012 extent was 633k km2 more than 2018 on this date and yet still ended up with a record low by 700,000 km2.

I have added a line on the first table to show the effect of removing 2012 from the 10 year average extent loss. The outcome for the minimum then comes in at 4.12 million km2 as opposed to 3.96 million km2.
"Para a Causa do Povo a Luta Continua!"

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #610 on: May 18, 2018, 05:43:47 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 17th, 2018: 11,588,270 km2, a drop of -42,574 km2.
2018 is the second lowest on record.
2018 has 443,551 km2 more than 2016 and 163,294 km2 less than 2015.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #611 on: May 19, 2018, 05:51:16 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 18th, 2018: 11,520,403 km2, a drop of -67,867 km2.
2018 is the second lowest on record.
2018 has 416,150 km2 more than 2016 and 155,259 km2 less than 2015.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #612 on: May 19, 2018, 12:58:18 PM »
JAXA DATA 11,520,403 km2(May 18, 2018)

Just to add to Juan's post :
- Extent loss was below average for the previous 4 days, but on 18th May up a bit above avergae, hence 2018 extent is now just 306k km2 less than 2017,
- 2012 extent was 646k km2 more than 2018 on this date and yet still ended up with a record low by 700,000 km2. We are approaching the time when 2012 extent loss started to accelerate

I have added a line on the first table to show the effect of removing 2012 from the 10 year average extent loss. The outcome for the minimum then comes in at 4.13 million km2 as opposed to 3.97 million km2. The range of outcomes from the last 10 years remaining melt is 2.5 to 4.5 million km2.
"Para a Causa do Povo a Luta Continua!"

Lord M Vader

  • ASIF Upper Class
  • Posts: 1167
    • View Profile
  • Liked: 3
  • Likes Given: 0
Re: 2018 sea ice area and extent data
« Reply #613 on: May 19, 2018, 06:14:10 PM »
NSIDC reports a big fat Century Break. Down 110K to 12,088 Mn km2.

Sigmetnow

  • ASIF Emperor
  • Posts: 11267
    • View Profile
  • Liked: 15
  • Likes Given: 7
Re: 2018 sea ice area and extent data
« Reply #614 on: May 20, 2018, 12:16:15 AM »
“#Arctic sea ice extent has remained more than 2 standard deviations below the climatological average for nearly all of 2018 to-date
Graphics: http://sites.uci.edu/zlabe/arctic-sea-ice-extentconcentration/  “

https://twitter.com/zlabe/status/997883514925211648
Image below.
People who say it cannot be done should not interrupt those who are doing it.

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #615 on: May 20, 2018, 05:44:19 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 19th, 2018: 11,434,743 km2, a drop of -85,660 km2.
2018 is the second lowest on record.
2018 has 393,517 km2 more than 2016 and 176,359 km2 less than 2015.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #616 on: May 21, 2018, 06:44:14 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 20th, 2018: 11,374,694 km2, a drop of 60,049 km2.
2018 is the second lowest on record.
2018 has 384,740 km2 more than 2016 and 138,836 km2 less than 2015.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #617 on: May 22, 2018, 05:49:09 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 21st, 2018: 11,304,168 km2, a drop of 70,526 km2.
2018 is the second lowest on record.
2018 has 352,325 km2 more than 2016 and 136,626 km2 less than 2015.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #618 on: May 23, 2018, 05:44:02 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 22nd, 2018: 11,269,417 km2, a drop of 34,751 km2.
2018 is the second lowest on record.
2018 has 345,454 km2 more than 2016 and 104,006 km2 less than 2015.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #619 on: May 23, 2018, 05:36:55 PM »
To be away from any telecomms signal for days again - it was bliss!
Postings will continue to be somewhat erratic for a month or so.

JAXA Extent 11,269,417 km2(May 22, 2018)

Just to add to Juan's post :
- Extent loss for the melting season to date is, at 2.62 million km2, almost exactly the average for the last 10 years.
- 2017 was a slow year at this time, hence 2018 extent is 446k (4%) below 2017,
- 2012 extent was 655k km2 more than 2018 on this date and yet still ended up with a record low by a bit more than 800,000 km2. We are approaching the time when 2012 extent loss started to accelerate.
- 2007 has a similar story - extent 620k more than 2018 on this date but melt accelerated late in the season.
- on average 26% of the melting is done for this season - still a long way to go,

I have added a line on the first table to show the effect of removing 2012 from the 10 year average extent loss. The outcome for the minimum then comes in at 4.11 million km2 as opposed to 3.95 million km2. The range of outcomes from the last 10 years remaining melt is 2.5 to 4.4 million km2.

Some non-data, non-scientific comments:-
- The Arctic in 2018 is a bit warmer so far than 2017,
- Global Ocean Heat Content has increased strongly in the last 12 months, some will head north.
- ENSO neutral conditions apply in 2018 as opposed to weakish La Nina in 2017.

These indicate a stronger melt this year than last year - maybe.
"Para a Causa do Povo a Luta Continua!"

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #620 on: May 24, 2018, 05:51:29 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 23rd, 2018: 11,226,696 km2, a drop of -42,721 km2.
2018 is the second lowest on record.
2018 has 346,377 km2 more than 2016 and 89,751 km2 less than 2015.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Daniel B.

  • ASIF Middle Class
  • Posts: 569
    • View Profile
  • Liked: 1
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #621 on: May 24, 2018, 02:01:14 PM »
Thus far, 2018 has been roughly paralleling the melt years of 2009, 11, and 15.  Those years finished 11th, 4th, and 5th lowest minima respectively, after reaching 10th, 5th, and 3rd highest maxima.  That pace, should it continue, would place 2018 at 4th lowest.

jdallen

  • ASIF Governor
  • Posts: 2597
    • View Profile
  • Liked: 10
  • Likes Given: 16
Re: 2018 sea ice area and extent data
« Reply #622 on: May 24, 2018, 03:28:03 PM »
Thus far, 2018 has been roughly paralleling the melt years of 2009, 11, and 15.  Those years finished 11th, 4th, and 5th lowest minima respectively, after reaching 10th, 5th, and 3rd highest maxima.  That pace, should it continue, would place 2018 at 4th lowest.
For me, quasi-statistical estimations based on graph morphology  like this have failed miserably every time I've made one.  Based on that, the only guess I'll hazard at this juncture is the season will finish somewhere between 1st  and 10th lowest minima. 😁
This space for Rent.

Archimid

  • ASIF Upper Class
  • Posts: 1067
    • View Profile
  • Liked: 15
  • Likes Given: 17
Re: 2018 sea ice area and extent data
« Reply #623 on: May 24, 2018, 03:44:09 PM »
Quote
quasi-statistical estimations based on graph morphology

Thanks for that. I tend to do this a lot. Your description of the method really puts in perspective for me.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Dharma Rupa

  • ASIF Citizen
  • Posts: 206
    • View Profile
  • Liked: 1
  • Likes Given: 7
Re: 2018 sea ice area and extent data
« Reply #624 on: May 24, 2018, 04:30:11 PM »
Quote
quasi-statistical estimations based on graph morphology

Thanks for that. I tend to do this a lot. Your description of the method really puts in perspective for me.

The graphs and data are very good at telling us where we've been, and pretty good at telling us where we are.

Daniel B.

  • ASIF Middle Class
  • Posts: 569
    • View Profile
  • Liked: 1
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #625 on: May 24, 2018, 04:43:39 PM »
Thus far, 2018 has been roughly paralleling the melt years of 2009, 11, and 15.  Those years finished 11th, 4th, and 5th lowest minima respectively, after reaching 10th, 5th, and 3rd highest maxima.  That pace, should it continue, would place 2018 at 4th lowest.
For me, quasi-statistical estimations based on graph morphology  like this have failed miserably every time I've made one.  Based on that, the only guess I'll hazard at this juncture is the season will finish somewhere between 1st  and 10th lowest minima. 😁
That is about the best we can do.  Any individual year can have idiosyncrasies that lead to a much higher or lower minimum than expected otherwise.  Currently, I would say we have a low probability of a 1st or 10st lowest minimum, and higher probability of landing in between.  As the melting season proceeds, we can start eliminating other values, as being similarly unlikely.  In the end, several factors will come together, resulting in the final measurement, leaving everyone scratching their heads as to why this year did exactly what it did.

Wherestheice

  • ASIF Lurker
  • Posts: 57
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: 2018 sea ice area and extent data
« Reply #626 on: May 24, 2018, 07:30:43 PM »
Thus far, 2018 has been roughly paralleling the melt years of 2009, 11, and 15.  Those years finished 11th, 4th, and 5th lowest minima respectively, after reaching 10th, 5th, and 3rd highest maxima.  That pace, should it continue, would place 2018 at 4th lowest.

Based on the extent currently being 2nd lowest. A lot can happen. I think it’s fair to say if the conditions are right, a record low minimum is likely, but maybe we will luck out and have another summer like last year.... i doubt that. The arctic is transitioning into an ice-free state, so using past data won’t do much

litesong

  • ASIF Lurker
  • Posts: 96
    • View Profile
  • Liked: 4
  • Likes Given: 0
Re: 2018 sea ice area and extent data
« Reply #627 on: May 24, 2018, 07:38:31 PM »
   Any individual year can have idiosyncrasies that lead to a much higher or lower minimum than expected otherwise.
Do you think 2018 or other near future years will return to the high Arctic sea ice extents & volumes of the average of the 1980's?

Daniel B.

  • ASIF Middle Class
  • Posts: 569
    • View Profile
  • Liked: 1
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #628 on: May 24, 2018, 08:34:02 PM »
   Any individual year can have idiosyncrasies that lead to a much higher or lower minimum than expected otherwise.
Do you think 2018 or other near future years will return to the high Arctic sea ice extents & volumes of the average of the 1980's?
Not in 2018 or the near future.  Eventually, yes.


Hyperion

  • ASIF Citizen
  • Posts: 221
  • Admiral Franklin of the McGillicuddy Highland Navy
    • View Profile
  • Liked: 8
  • Likes Given: 0
Re: 2018 sea ice area and extent data
« Reply #629 on: May 24, 2018, 11:10:50 PM »
   Any individual year can have idiosyncrasies that lead to a much higher or lower minimum than expected otherwise.
Do you think 2018 or other near future years will return to the high Arctic sea ice extents & volumes of the average of the 1980's?
Not in 2018 or the near future.  Eventually, yes.
I agree. Possibly about 130 million years from now it may. Earth has roughly followed a 50million year glaciated, 100 million year ice free hothouse cycle for about the last billion years. The unprecedented in the last billion years rate of warming, and ecocide humans have achieved virtually guarantees that we have ended the recent 50 million year glacial. If we are lucky we may not have set off a Venus style runaway water vapour greenhouse warming. Let's cross our fingers and hope that near or all non photosynthetic life will be wiped out instead, and extremophile cyanobacteria put the earth in a snowball state for a hundred million years or so to reboot the ecosphere.
Planet scale bio-sterilization would not be a nice Karmic burden for the human soul-family
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
https://en.wikipedia.org/wiki/McGillicuddy_Serious_Party

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #630 on: May 25, 2018, 06:03:37 AM »
[ADS-NIPR-JAXA] ASI Extent.

May 24th, 2018: 11,162,193 km2, a drop of -64,503 km2.
2018 is the second lowest on record.
2018 has 369,528 km2 more than 2016 and 113,469 km2 less than 2015.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #631 on: May 25, 2018, 10:37:08 AM »
JAXA Extent 11,162,193 km2(May 24, 2018)

Just to add to Juan's post :
- Extent loss for the melting season to date is, at 2.73 million km2, almost exactly the average for the last 10 years.
- 2017 was a slow year at this time, hence 2018 extent is 439k (3.9%) below 2017,
- 2012 extent was 684k km2 more than 2018 on this date and yet still ended up with a record low by a bit more than 800,000 km2. We are approaching the time when 2012 extent loss started to accelerate.
- 2007 has a similar story - extent 622k more than 2018 on this date but melt accelerated late in the season.
- on average 28% of the melting is done for this season - still a long way to go,

I have added a line on the first table to show the effect of removing 2012 from the 10 year average extent loss. The outcome for the minimum then comes in at 4.11 million km2 as opposed to 3.95 million km2. The range of outcomes from the last 10 years remaining melt is 2.5 to 4.4 million km2.

Some non-data, non-scientific comments:-
- The melt this year for some time has seen very little variation from plodding along at 2nd place, hence this post shows little variation from the previous post,
- The Arctic in 2018 is a bit warmer so far than 2017,
- Global Ocean Heat Content has increased strongly in the last 12 months, some will head north.
- ENSO neutral conditions apply in 2018 as opposed to weakish La Nina in 2017.

These indicate a stronger melt this year than last year - maybe. But pure speculation without data belongs not on this thread nor on the 2018 melting season thread.
"Para a Causa do Povo a Luta Continua!"

gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #632 on: May 25, 2018, 02:34:34 PM »
NSIDC Total Area as at 24 May (5 day trailing average) 10,402,675 km2

The great warming event continues to be promised by GFS, but always at the end of the 10 day forecast period. However, it is warming up from the Russian side.

I is tired so here are the tables without comments. Methinks I will post the area graphs soon as they show more.
"Para a Causa do Povo a Luta Continua!"

Shared Humanity

  • ASIF Governor
  • Posts: 2701
    • View Profile
  • Liked: 27
  • Likes Given: 2
Re: 2018 sea ice area and extent data
« Reply #633 on: May 25, 2018, 02:45:11 PM »
gerontocrat...

I want to thank you for these great posts! You have made this thread a must visit for me. Every morning, I come to review yours and Juan's data and analysis every day.

Shared Humanity

  • ASIF Governor
  • Posts: 2701
    • View Profile
  • Liked: 27
  • Likes Given: 2
Re: 2018 sea ice area and extent data
« Reply #634 on: May 25, 2018, 02:58:17 PM »
Thought I would post the regional extent graphs with a few comments.

CAB: Recent melt as placed the CAB in the lead as compared to other seasons.
Greenland Sea: With low extent throughout the winter, this sea continues to remain historically low.
Baffin/Newfoundland Bay: After a 2 month stall, melt has ramped up with extent about average at this point in the season.
Chukchi: The early melt has kept this sea in the lead.
Bering: With an historically low winter maximum, the Bering is completely melted out and will have no more impact on the extent number for the remainder of the season.

Shared Humanity

  • ASIF Governor
  • Posts: 2701
    • View Profile
  • Liked: 27
  • Likes Given: 2
Re: 2018 sea ice area and extent data
« Reply #635 on: May 25, 2018, 03:02:08 PM »
And here are the regional area graphs.

Kara Sea: Stubbornly resisting melt early in the season.

I've always thought that comparing area to extent performance could reveal insights about the melt season but I don't see anything of note at the moment. Area and extent for the regions seem to be tracking closely.

Juan C. García

  • ASIF Middle Class
  • Posts: 602
    • View Profile
  • Liked: 16
  • Likes Given: 13
Re: 2018 sea ice area and extent data
« Reply #636 on: May 26, 2018, 06:12:47 AM »
Sorry, guys...

There is a delay of 30+ minutes on JAXA data.
It makes me think that we will not have information this weekend.
You can check if the data has been updated:

https://ads.nipr.ac.jp/vishop/#/extent
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

epiphyte

  • ASIF Citizen
  • Posts: 343
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: 2018 sea ice area and extent data
« Reply #637 on: May 26, 2018, 06:31:33 AM »
And here are the regional area graphs.

Kara Sea: Stubbornly resisting melt early in the season.

I've always thought that comparing area to extent performance could reveal insights about the melt season but I don't see anything of note at the moment. Area and extent for the regions seem to be tracking closely.

It appears to me that right now the land is keeping the ice cold, rather than the other way round.

...That can't be good.


gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #638 on: Today at 02:27:11 PM »
I've always thought that comparing area to extent performance could reveal insights about the melt season but I don't see anything of note at the moment. Area and extent for the regions seem to be tracking closely.

The two tables below show a summary of extent loss and area loss for the 10th to 26th May (NSIDC data).

You will see that extent loss especially for the Central Seas is much less than area loss simply because of the 15% rule for registering extent). In most of the peripheral seas extent loss is now playing catch-up with area. Area loss therefore will show when melting is underway earlier - while extent is a lagging indicator. It is also a better indicator of the true extent to which each sea is ice-covered.

I will always use extent for the multi-year Arctic /Antarctic total stuff simply because that's the way it is, and who am I to take on NASA, the NOAA, the NSIDC etc etc etc?
"Para a Causa do Povo a Luta Continua!"

gerontocrat

  • ASIF Upper Class
  • Posts: 1951
    • View Profile
  • Liked: 84
  • Likes Given: 6
Re: 2018 sea ice area and extent data
« Reply #639 on: Today at 03:15:18 PM »
NSIDC Total Area as at 26 May (5 day trailing average)

The table attached in the post above shows how area loss has switched to lower in the peripheral seas and much higher in the Central Seas and is maintaining a 50+k km2 loss per day.

Pacific Side
- The Okhotsk Sea area is down to 38k km2, well under 5% of historical average maximum, daily - loss has slowed to 1 to 2k and is more or less irrelevant.
- The Bering Sea area is 4k, and is irrelevant (except to see for how long the vestiges of ice will persist).
- Chukchi and Beuafort Sea losses are modest.

Atlantic Side

- Area loss in the Baffin, Greenland, and Barents Seas seems to have slowed somewhat. area loss in the last two days was 13k.
- The Laptev Sea lost 26k on the 26th May, over half the loss of the Central seas.
- The Kara Sea is steadily losing area.
- Other Central Seas area loss is minimal.

Other seas
- St Lawrence continues to hang on to its area of 13k,
- Hudson Bay increased in extent in the last two days.

The great warming event predicted by GFs is again postponed to the end of the 10 day forecast However,GFS from cci-reanalyzer.org shows  there is a believable significant influx of warm air from the Russian side happening now and in the next few days.

Warmth looks as if it will hit the southern half of Hudson Bay as well. Can I believe the BBC when its says next Tuesday temps in Churchill will max at 21 degrees celsius?
"Para a Causa do Povo a Luta Continua!"

numerobis

  • ASIF Middle Class
  • Posts: 772
    • View Profile
  • Liked: 13
  • Likes Given: 0
Re: 2018 sea ice area and extent data
« Reply #640 on: Today at 04:29:41 PM »
According to Windy: forecast for Tuesday 3pm in Churchill has ECMWF at 15 C, GFS at 19 C, NEMS at 20 C.

The temperature gradient from inshore to the sea is very steep. In all three models you get mid-20s not far from Churchill. I presume there must not be much snow left inland (the rail line got wiped out by flooding in April last year, so that must be about when the snow largely melts).